PDF(Pubmed)
Abstract：
Contractile injection systems (CISs) are prokaryotic phage tail-like nanostructures loading effector proteins that mediate various biological processes. Although CIS functions have been diversified through evolution and hold the great potential as protein delivery systems, the functional characterisation of CISs and their effectors is currently limited to a few CIS lineages. Here, we show that the CISs of Streptomyces davawensis belong to a unique group of bacterial CISs distributed across distant phyla and facilitate sporogenic differentiation of this bacterium. CIS loss results in decreases in extracellular DNA release, biomass accumulation, and spore formation in S. davawensis. CISs load an effector, which is a remote homolog of phage tapemeasure proteins, and its C-terminal domain has endonuclease activity responsible for the CIS-associated phenotypes. Our findings illustrate that CISs can contribute to the reproduction of bacteria through the action of the effector and suggest an evolutionary link between CIS effectors and viral cargos.
摘要：
收缩注射系统(CIS)是装载介导各种生物过程的效应蛋白的原核噬菌体尾巴状纳米结构。尽管CIS功能已经通过进化多样化，并具有作为蛋白质递送系统的巨大潜力，CISs及其效应子的功能表征目前仅限于几个CIS谱系。这里,我们表明，大卫链霉菌的CISs属于分布在远处门的一组独特的细菌CISs，并促进该细菌的孢子形成分化。CIS损失导致细胞外DNA释放减少，生物量积累，和S.davawensis的孢子形成。CISs加载效应器，这是噬菌体检测蛋白的远程同源物，并且其C末端结构域具有负责CIS相关表型的核酸内切酶活性。我们的发现表明，CISs可以通过效应子的作用促进细菌的繁殖，并表明CIS效应子与病毒货物之间存在进化联系。
